More efficient aboveground nitrogen use in more diverse Central European forest canopies Martin T. Schwarz ∗† , Sebastian Bischoff ‡ , Stefan Blaser § , Steffen Boch § , Barbara Schmitt § , Lisa Thieme ¶ , Markus Fischer § , Beate Michalzik ‡ , Ernst-Detlef Schulze ‖ , Jan Siemens ¶ , Wolfgang Wilcke ∗∗ Published under Copyright© of Elsevier B.V. 2013: Schwarz, M. T., Bischoff, S., Blaser, S., Boch, S., Schmitt, B., Thieme, L., Fis- cher, M., Michalzik, B., Schulze, E.-D., Siemens, J. & W. Wilcke. (2014). More efficient aboveground nitrogen use in more diverse Central European forest canopies. For. Ecol. Manage. 313: 274-282. doi:10.1016/j.foreco.2013.11.021. Abstract We hypothesized that biodiversity improves ecosystem functioning and services such as nu- trient cycling because of increased complemen- tarity. We examined N canopy budgets of 27 Central European forests of varying dom- inant tree species, stand density, and tree ∗ Corresponding author: M.T.Schwarz@outlook.com † University of Berne, Institute of Geography, Haller- strasse 12, 3012 Berne, Switzerland ‡ Friedrich Schiller University of Jena, Institute of Ge- ography, Löbdergraben 32, 07743 Jena, Germany § University of Berne, Institute of Plant Sciences and Botanical Garden, Altenbergrain 21, 3013 Berne, Switzerland ¶ Rheinische Friedrich Wilhelms University of Bonn, Institute for Crop Science and Resource Conserva- tion, Division Soil Science and Soil Ecology, Nus- sallee 13, 53115 Bonn, Germany ‖ Max Planck Institute for Biogeochemistry, Hans- Knöll-Strasse 10, 07745 Jena, Germany ∗∗ Karlsruhe Institute of Technology (KIT), Institute of Geography and Geoecology, Reinhard-Baumeister- Platz 1, 76131 Karlsruhe, Germany and shrub species diversity (Shannon index) in three study regions by quantifying bulk and fine particulate dry deposition and dissolved below canopy N fluxes. Average regional canopy N retention ranged from 16% to 51%, because of differences in the N status of the ecosystems. Canopy N budgets of coniferous forests differed from deciduous forest which we attribute to differences in biogeochemical N cycling, tree functional traits and canopy surface area. The canopy budgets of N were related to the Shan- non index which explained 14% of the variance of the canopy budgets of N, suggesting com- plementary aboveground N use of trees and di- verse understorey vegetation. The relationship between plant diversity and canopy N reten- tion varied among regional site conditions and forest types. Our results suggest that the tradi- tional view of belowground complementarity of nutrient uptake by roots in diverse plant com- munities can be transferred to foliar uptake in forest canopies. Keywords • Terrestrial nitrogen cycling • Nitrogen deposition • Canopy N retention • Ecosystem functioning • Complementarity • Biodiversity Exploratories 1